Throughout modern times liberal states have always co-existed alongside many kinds of tyranny. Similarly, the modern world has always contained numerous economic systems - many varieties of capitalism, planned and guided economies, and a host of hybrid economic systems not easily classified.
Diplomacy and international law developed to cope with the fact of diverse regimes. Yet throughout the 20 th century global politics was shaped by the project of unifying the world within a single regime. Insofar as it remained committed to Marxist ideology, the long-term goal of the Soviet regime was world communism. The whole world was to be a single socialist economy, administered by forms of governance that were to be everywhere the same.
This Marxist project is now widely and rightly viewed as utopian. Even so, its disappearance as a force in world politics has not been accompanied by an acceptance of a diversity of political systems. With communism's fall we were, in Francis Fukuyama's famous phrase, at the "end of history", a time when western governments could dedicate themselves to unifying the international system into a single regime based on free markets and democratic government. But this project is as utopian as Marxism once was, and promises to be considerably more short-lived than the Soviet Union.
Many reasons exist for why the Soviet bloc collapsed, but--contrary to conventional opinion--economic inefficiencies were not central among them. The Soviet bloc disintegrated because it could not cope with nationalist dissent in Poland and the Baltic states and more generally because a single economic and political system could not meet the needs of vastly different societies and peoples.